The ability to accurately and reliably determine the presence or otherwise of a particular compound on an everyday object is of significant importance to customs and police forces around the world. The compounds of highest interest include illicit drugs and explosives and it is their detection in both a forensic context and with regards to the detection of contraband or tariff evasion that is of interest to police and custom forces respectively. Generally, the compounds of interest are likely to be present only in extremely small, or trace, amounts. Consequently, extremely sensitive chemical analysis techniques are employed to determine the presence or otherwise of a particular compound.
One such analytical approach known from the prior art is to use a tandem mass spectrometer to chemically analyse a collected sample. Traditional techniques for the preparation of the samples prior to analysis by the mass spectrometer typically include complex and time consuming purification and chemical treatment steps involving the use of solvents and glassware. The sample preparation techniques inhibit the use of tandem mass spectrometers as part of a “real-time” security process, such as a part of the security checks applied to a traveller prior to boarding an aeroplane.
In UK patent application GB 2363517 A, the current applicants discuss the introduction of a sample to a mass spectrometer by heating a sheet-like carrier, such as a bank note or an aeroplane ticket, within a confined space between two heated bodies such that a sufficient quantity of substance is desorbed from the carrier to be passed directly into the ionisation chamber of a mass spectrometer for analysis. The use of a carrier transport system involving pairs of rollers to enable a number of separate carriers to be analysed in succession is also discussed.
U.S. Pat. No. 4,705,413 discloses a roller mechanism for compensating for thickness of pieces of mail in a mailing machine. A reaction (idle) roller is provided with a single suspension element acting on the centre of the idle roller. There is no disclosure of surmounting the problems associated with providing suspension for driven rollers.
It is to improvements in the transport system for the analysis apparatus that this present application relates.